( function () {
/**
 * Unpack RGBA depth shader
 * - show RGBA encoded depth as monochrome color
 */
const UnpackDepthRGBAShader = {
  uniforms: {
    'tDiffuse': {
      value: null
    },
    'opacity': {
      value: 1.0
    }
  },
  vertexShader:
  /* glsl */
  `

		varying vec2 vUv;

		void main() {

			vUv = uv;
			gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );

		}`,
  fragmentShader:
  /* glsl */
  `

		uniform float opacity;

		uniform sampler2D tDiffuse;

		varying vec2 vUv;

		#include <packing>

		void main() {

			float depth = 1.0 - unpackRGBAToDepth( texture2D( tDiffuse, vUv ) );
			gl_FragColor = vec4( vec3( depth ), opacity );

		}`
};

THREE.UnpackDepthRGBAShader = UnpackDepthRGBAShader;
} )();
